Ignition distributor



Patented Oct. 18, 1938 UNITED STATES PATENT OFFICE eral Motors Corporation, poration of Delaware Detroit, Mich., a cor- Application August 10, 1935, Serial No. 35,604

11 Claims.

This invention relates to ignition timers and is directed particularly to timers of the suction control type or that in which there is incorporated a movable circuit breaker plate.

One object of the invention is to provide a suction controlled timer having a shiftable breaker plate mounted on ball bearings and responsive to the controlling unit with the least amount of frictional resistance.

Another object of the invention is to provide a movable breaker plate for a timer that will faithfully follow any and all lateral movement of the circuit breaker actuating means so as to avoid variation in contact opening due to shaft wobble and/or bearing wear.

Another object of the invention is to provide an oscillatable support for a circuit breaker mechanism whereby variation of contact opening during operation may be substantially eliminated.

Still another object is to provide a movable circuit breaker plate that has a ball bearing support on an actuating shaft.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

Fig. 1 is a plan View of the ignition distributor with the distributor cap removed and illustrating the invention as applied to a distributor of the engine suction control type.

Fig. 2 is a vertical section of the ignition distributor with its distributor cap substantially as indicated by the line and arrows 22 of Fig. 1.

Fig. 3 is a detailed view in cross section, of a linkage between the suction control unit and a movable breaker plate, substantially as indicated by the line and arrows 3-3 of Fig. 1.

Fig. 4 is a fragmentary view illustrating the stop means by which movement of the breaker plate is limited, it being a view substantially as indicated by the line and arrows 4-4 of Fig. 1.

In ignition timer-distributors of that class wherein the timing is altered by means of a fluid displacement unit such as the usual suction chamber or control unit connected up with the intake of the engine, it is necessary to incorporate means to reduce the friction of breaker plate movement to as low a factor as possible. The most desirable solution of a problem of this kind is that of mounting the circuit breaker supporting plate upon ball bearings, and by reduction of the mass of the circuit breaker assembly so as to make use of all the energy possible of the suction unit.

While there are a considerable number of socalled ball bearing ignition distributors in the prior art, the instant disclosure sets out improvements therein by which the greatest efficiency can be obtained. The objects set out herein are accomplished and the invention disclosed is perfected by mounting the circuit breaker plate on a two row ball bearing assembly that is rigidly supported on the usual circuit breaker operating cam. In a construction of that import the circuit breaker plate then gets its support wholly from the cam, and while the cam is rotating should it be slightly out of true the circuit breaker plate will follow all lateral movement of the cam, so that there will be uniform operation of contact opening, without the usual variations of contact opening that usually obtain in ignition timer-distributors of the prior art.

For more detailed explanation of the improvements, reference is now made to the attached drawing, wherein l indicates a timer-distributor housing of cup-shaped formation having a shank l2 and an upstanding boss l4 formed with a bore to provide a bearing for a shaft IB, operable to drive a cam l8 through an articulated speed re sponsive or centrifugal mechanism 20. In driving relation with the cam [8 there is a rotor 22 having a wiping contact 24, spring urged to engage a terminal insert 26 secured within a disu tributor cap 28 mounted on and closing off the open end of the housing I0, the cap 28 being held in place by the usual spring clips 30. The rotor 22 likewise is provided with a segment 32 adapted to pass by spark plug terminal sockets 34 also secured within the cap 28 and thereby distribute the spark impulse to the proper engine cylinder.

Secured in the bottom of the housing [0, there is a press fitted closure means 36 that is spaced from the bottom wall of the cup and thereby forms a lubricant aperture 38, from which cross bores bore of the extension l2 for lubricating the shaft l6, and by which lubricant finds its way to the oil groove 42 broached in the bearing bore. Lubricant is admitted to the chamber 38 by the convenient fitting 44.

The speed responsive mechanism 20 comprises a plate 46 press fitted upon the part 48 of the shaft 16, and provides a pair of pivot pins 50 oscillatably supporting flyweights 52, each of which has an arm engaging a cam bar 54 secured to the lower end of the cam l8 as by press fitting or the like. The cam bar 54 is provided with spring 40 make communication with the bearing a diaphragm I46,

posts 56 and 58 to which springs 66 are secured and thence hooked over the pivot pins 50 so as to act in a retracting manner on the flyweights 52. The spring post 56 extends through the cam bar 54 into an aperture 62 of the plate 46 and thereby acts as a stop determining the relative amount of rotation permissible between the shaft I6 or its extension 64, and the cam I8. Th s speed responsive mechanism is fully illustrated, described and claimed in a patent to J. T. Fitzsimmons No. 1,753,564, granted 'April 8, 1930, to which reference is made for more detailed description thereof.

Concentrically disposed about the cam I8, as is shown in Fig. 1, there is a movable breaker plate 66 on which is mounted a bracket 68 supporting a fixed contact I and a pivot post I2, that oscillatably supports a breaker lever I4 provided with a movable contact I6. Thepivot post I2 is firmly fixed in the plate 66 and forms a journal pin about which the bracket 68 oscillates by means of an eccentric device 'IB, and which is held in place by a clamp screw '80. A breaker lever I4 is provided with a rubbing block 82 and supports one end of a spring conductor 84 fixed to a terminal screw 66 insulatedly supported by a lug 88 struck up from the plate 66. From the terminal screw 86 there extends a lead 90 that communicates with a terminal post 92 secured in the wall of the housing III, and a lead 94 extends to a condenser 96 secured and grounded to the structure through a clip 98 and a holddown screw I60. To insure that the condenser is actually grounded, a third lead I02 is joined to the plate 66 by a clip I04 and thence to the wall of the housing III by a screw device The breaker plate 66 has its support by a two row ball bearing assembly III], and is accom-. plished by providing a central aperture H2 in the plate concentric with the cam and so as to pass thereover, the edge portion of the aperture I I2 being struck laterally at a plurality of points, there being three in the illustrated embodiment, at H4 so as to provide three depending lugs or tongues I I6 that are concentric with the aperture H2. Tightly fitting within these tongues H6 substantially in telescopic engagement therewith is an outer race member II8 against Which are disposed ball bearings I26 of one row and I 2 2 of a second row, held in place by an inner ring or race member I24, press fitted or otherwise secured upon the cam I8 or an, extension thereof so as to be rotatable therewith. As an aid in securing the outer race H8 in its telescopic engagement with the tongues I I6, and for securing it to the plate 66, holddown clips I36 are provided that have extensions I32 hooking over the edge of the race member I58, and branches I34 apertured to receive a clamp screw I36 passing through appropriate slots I31 in the plate 66. If desired, the ground lead clip I64 may also be secured by one of the screws I36 which also operates to hold the clip I30. Encircling the lower end of the cam and'disposed between the race member I24 and the cam bar 54, there are a sufficient number of spacers I38 and I39 to prevent the parts from becoming disassembled.

Attached to the housing III there is a press metal bracket I46 secured in place by means of screws I42, the bracket I46 supporting a suction unit I44 that encloses a fluid operated provided with a link I48 apertured at I50 toembrace a bearing pin I52 secured in the edge of the plate 66. An appropriate nip= ple I54 provides for communication with the intake pipe of an engine, and admits low pressure to the unit I44 upon the occurrence of which the diaphragm or displacement member I46 compresses a restoring spring I56, and pulls upon the link I48 to move the plate 66. The link I48 is necked at I58, and at that point passes through an elongated aperture I66 in the back of the housing member I62 of the chamber I44, and thereby provides stop means determining the limits of movement of the plate by the control unit.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of claims which follow.

What is claimed is as follows:

1. A timer-distributor comprising in combination, a housing, a shaft and a cam supported thereby rotatable within the housing, a circuit breaker plate, a ball bearing assembly supporting the plate from the cam, and means for oscillating the plate on the bearing.

2. In a tii'ner-distributor the combination comprising, an actuating shaft, a housing providing a bearing for the shaft, a cam driven by the shaft, a breaker plate within the housing, a ball bearing assembly supporting the plate from the cam, and means for oscillating the plate about the cam and through the ball'bearing assembly.

3. In a timer-distributor, the combination comprising, a housing, an actuating shaft journalled in the housing, a cam driven by the shaft, a breaker plate movable within the housing and supported for oscillation about the cam, said support comprising ball race members fixed relative to the cam and the breaker plate.

4. In a timer-distributor the combination comprising, a shaft, a cam driven by the shaft,

a breaker plate, a circuit breaker secured to the plate to be operated by the cam, means rotatably supporting the plate from the cam and causing the plate to follow the wobble of the shaft, whereby the contact opening of the circuit breaker will be unvarying, said means comprising a two row ball bearing carried by the cam and rigidly supporting the breaker plate.

5. In a timer-distributor the combination comprising a housing, a shaft journalled in the housing, a cam driven by the shaft, a breaker plate, a circuit breaker secured to the plate to be operated by the cam, means rotatably supporting the plate relative to the cam permitting oscillation of the plate relative to the housing, and causing the plate to follow all lateral mo tion of the cam, said means comprising an inner race member secured to the cam, an outer race member secured to the plate, and two rows of balls between the race members, rotation of the shaft within its journal causing the cam to rotate relative to the breaker plate, and the ball bearing support causing the plate to follow all lateral motion of the rotating cam.

6. In a ball bearing timer-distributor having a housing with a shaft journaled in the housing and supporting a cam to be driven thereby, and a circuit breaker to be operated by the cam, the combination with said cam and circuit breaker of, a movable breaker plate supporting the circuit breaker, and means providing a ball bearing support from the cam for the breaker plate, and means maintaining the breaker plate relatively fixed with respect to the cam, whereby actuation of the cam will cause the same to rotate within the breaker plate.

'7. In a ball bearing timer-distributor having a housing with a shaft journaled in the housing and supporting a cam to be driven thereby, and a circuit breaker to be operated by the cam, the combination with said cam and circuit breaker of, a breaker plate supporting the circuit breaker and symmetrically disposed within the housing about the cam, a two row ball bearing having an inner race secured to the cam and an outer race secured to the plate, and means limiting the movement of the plate about the cam and operable to shift the plate relative to the housing, whereby rotation of the cam will be relative to the plate and cause the plate to follow all lateral movement of the cam during rotation.

8. In a ball bearing timer-distributor having a housing with a shaft journaled in the housing and supporting a cam to be driven thereby, and a circuit breaker to be operated by the cam, the combination with said cam and circuit breaker of, means supporting the circuit breaker from the shaft including a two row ball bearing whereby variations in contact opening due to shaft wobble will be eliminated.

9. In a ball bearing timer-distributor having a housing with a shaft journaled in the housing and supporting a cam to be driven thereby, and a circuit breaker to be operated by the cam, the combination with said cam and circuit breaker of, an apertured plate symmetrically disposed about the cam and supporting the circuit breaker for operation thereby, a two row ball bearing assembly supporting the plate from the cam and comprising, an inner race secured to the cam, an outer race telescopically received by portions of the plate, and a holddown clip retaining the plate upon the outer race.

10. The combination set forth in claim 9 in which the breaker plate has laterally extending integrally formed tongues concentric with the aperture thereof for firm engagement about the ball bearing assembly.

11. The combination set forth in claim 9 in which the means for securing the breaker plate to the ball bearing assembly include Z-shaped clips hooked over the edge of the ball bearing assembly and secured to the plate by screws threaded therethrough.

JAMES L. ARTHUR. 

